1. Technical Field
The present invention relates to a clutch apparatus for an automatic transmission, and more particularly, the present invention relates to a clutch apparatus for an automatic transmission, which is disposed between a flywheel of an engine and the automatic transmission in a motor vehicle to connect and disconnect engine power flow to the automatic transmission and to multiply torque.
2. Background Art
Generally, an engine of a motor vehicle cannot start in a state wherein a load is applied thereto and cannot transfer engine power to driving wheels at the same time when the engine starts. Also, on the contrary to the fact that the engine rotates only in one direction, the motor vehicle must be able to run in both forward and backward directions. By reason of these, a clutch is arranged between the engine and a transmission to enable the engine to start in a state wherein no load is applied thereto. The clutch should be able to gradually transfer engine power to the driving wheels to allow the motor vehicle to smoothly move and a speed changing operation to be adequately implemented relying upon driving circumstances. To this end, an automatic transmission which can simultaneously perform a clutching operation and a shift lever manipulating operation in an automated manner, had been developed.
An automatic transmission generally comprises a combination of a torque converter which performs a clutching operation and a transmission section (a planetary gear type transmission section) which performs a speed changing operation. As shown in FIG. 1, the torque converter 10 includes a pump 12, a turbine 14 and a stator 16 which are formed with vanes therein. In the torque converter 10, circulating flow in which oil inside a pump impeller is circulated through the pump 12, the turbine 14 and the stator 16 by centrifugal force, is produced by an engine. By this, the turbine 14 receives engine power to drive a driven shaft 20. In other words, the torque converter 10 simultaneously performs a function of an automatic clutch and of a torque multiplication. Engine power which is transferred to the driven shaft 20, automatically executes a speed changing operation through a hydraulic control mechanism in the transmission section 30, whereby the torque-multiplied engine power is transferred to the driving wheels.
However, the conventional torque converter suffers from defects in that, since the torque converter transfers engine power to the transmission section using fluid, power loss is increased due to fluid friction, etc., whereby a power transferring efficiency is diminished, passing and acceleration capability of the motor vehicle is deteriorated and a difficulty is imposed on obtaining a maximum speed. Moreover, because the conventional torque converter must be necessarily equipped with a complex hydraulic mechanism including the pump, the turbine, the stator and the like and a cooling device for cooling oil which is circulated through the hydraulic mechanism, an entire construction is complicated and manufacturing cost is elevated.
Furthermore, since force of a driven side of the motor vehicle cannot be transferred to a driving side of the motor vehicle along a reverse direction, an engine brake operation cannot be fulfilled, by which an adverse influence is imposed on safe driving. In addition, due to the fact that it is impossible to start the engine by pushing the motor vehicle, it is difficult to cope with an emergency situation such as discharge of a battery.
Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a clutch apparatus for an automatic transmission, which is structured using planetary gears, whereby a power transferring efficiency is increased, a simple construction is achieved and an engine brake operation can be effected.
In order to achieve the above object, according to a first aspect of the present invention, there is provided a clutch apparatus for an automatic transmission, which is arranged at an input end of the automatic transmission to connect and disconnect engine power flow to the automatic transmission and to transfer multiplied torque to the automatic transmission, the clutch apparatus comprising: a clutch base mounted to a flywheel of an engine and having a supporting boss which possesses a cylindrical configuration and is projectedly formed on an inner surface of the clutch base, the supporting boss having first spline grooves which are defined on a circumferential inner surface of the supporting boss; a clutch cover coupled to a circumferential outer portion of the clutch base and having a cylindrical configuration which is opened at one end in a manner such that a space is defined in the clutch cover, the clutch cover being formed, at a center portion of a closed surface thereof, with a center hole through which a driven shaft connected to the automatic transmission is inserted; an output shaft rotatably fitted at one end thereof through the clutch base and at the other end thereof through the center hole of the clutch cover, and having a sun gear which is formed on a circumferential outer surface of the output shaft and second spline grooves which are defined on a circumferential inner surface of the output shaft; a pair of one-way rotating bearings fitted around both ends of the output shaft, respectively, in a manner such that the output shaft can be rotated in one direction which is the same as a rotating direction of the flywheel and cannot be rotated in the other direction which is opposite to the rotating direction of the flywheel; a plurality of planetary gear sections each possessing a guide shaft and a planetary gear, the guide shaft having one end which is rotatably fitted through the clutch base and the other end which is rotatably supported by the clutch cover, the planetary gear being formed on a circumferential outer surface of the guide shaft and being meshed with the sun gear of the output shaft; a rotating member having an internal ring gear and third spline grooves, the internal ring gear being formed on a circumferential inner surface of the rotating member and being meshed with planetary gears of the plurality of planetary gear sections, the third spline grooves being defined on a circumferential outer surface of the rotating member; a multiple disc clutch member having a plurality of inner plates which are fitted around the rotating member and a plurality of outer plates which are fitted into the supporting boss of the clutch base and each of which is intervened between two adjoining inner plates, each inner plate having spline teeth which are formed on a circumferential inner surface thereof and are splined into the third spline grooves of the rotating member, each outer plate having spline teeth which are formed on a circumferential outer surface thereof and are splined into the first spline grooves of the supporting boss; a pressing plate disposed between the multiple disc clutch member and the clutch cover, the pressing plate being moved by pressing force which is applied thereto in a manner such that the inner plates and the outer plates are tightly engaged one with another and thereby are locked one to another, the pressing plate possessing an annular plate-shaped configuration; pressing means arranged between the pressing plate and the clutch cover for applying pressing force to the pressing plate; and pressing force adjusting means arranged in a circumferential space which is defined between circumferential outer portions of the clutch base and the clutch cover, in a manner such that each pressing force adjusting means is capable of pivoting movement for changing an axial position of the pressing plate and adjusting a magnitude of pressing force which is applied to the multiple disc clutch member, depending upon a magnitude of centrifugal force generated by rotating force which is transferred from the flywheel.
According to a second aspect of the present invention, there is provided a clutch apparatus for an automatic transmission, which is arranged at an input end of the automatic transmission to connect and disconnect engine power flow to the automatic transmission and to transfer multiplied torque to the automatic transmission, the clutch apparatus comprising: a clutch base mounted to a flywheel of an engine and having a supporting boss and a ring gear boss which are projectedly formed on an inner surface of the clutch base in a manner such that the ring gear boss is placed inward of the supporting boss, the supporting boss having first spline grooves which are defined on a circumferential inner surface of the supporting boss, the ring gear boss having a first internal ring gear which is formed on a circumferential inner surface of the ring gear boss; a clutch cover coupled to a circumferential outer portion of the clutch base and having a cylindrical configuration which is opened at one end in a manner such that a space is defined in the clutch cover, the clutch cover being formed, at a center portion of a closed surface thereof, with a center hole through which a driven shaft connected to the automatic transmission is inserted; an output shaft rotatably fitted at one end thereof through the clutch base and at the other end thereof through the center hole of the clutch cover, and having a sun gear which is formed on a circumferential outer surface of the output shaft and second spline grooves which are defined on a circumferential inner surface of the output shaft; a pair of one-way rotating bearings fitted around both ends of the output shaft, respectively, in a manner such that the output shaft can be rotated in one direction which is the same as a rotating direction of the flywheel and cannot be rotated in the other direction which is opposite to the rotating direction of the flywheel; a carrier having a first disc and a second disc which are coupled with each other by means of a plurality of connecting members in a manner such that the first disc and the second disc are spaced apart from each other by a predetermined distance, the first disc being rotatably brought into contact at one surface thereof with the inner surface of the clutch base by the medium of a first thrust bearing, the second disc being rotatably brought into contact with the clutch cover by the medium of a second thrust bearing; a plurality of double planetary gear sections fitted around the plurality of connecting members, respectively, in such a way as to be disposed in the carrier, and each having integrally formed thereon a first planetary gear and a second planetary gear which have different numbers of teeth or different modules, the first planetary gear being meshed with the first internal ring gear, the second planetary gear being meshed with the sun gear of the output shaft; a rotating member possessing a ring-shaped configuration and having a second internal ring gear and third spline grooves, the second internal ring gear being formed on a circumferential inner surface of the rotating member and being meshed with second planetary gears of the plurality of double planetary gear sections, the third spline grooves being defined on a circumferential outer surface of the rotating member, the second and first internal ring gears having different numbers of teeth or different modules; a multiple disc clutch member having a plurality of inner plates which are fitted around the rotating member and a plurality of outer plates which are fitted into the supporting boss of the clutch base and each of which is intervened between two adjoining inner plates, each inner plate having spline teeth which are formed on a circumferential inner surface thereof and are splined into the third spline grooves of the rotating member, each outer plate having spline teeth which are formed on a circumferential outer surface thereof and are splined into the first spline grooves of the supporting boss; a pressing plate disposed between the multiple disc clutch member and the clutch cover, the pressing plate being moved by pressing force which is applied thereto in a manner such that the inner plates and the outer plates are tightly engaged one with another and thereby are locked one to another, the pressing plate possessing an annular plate-shaped configuration; pressing means arranged between the pressing plate and the clutch cover for applying pressing force to the pressing plate; and pressing force adjusting means arranged in a circumferential space which is defined between circumferential outer portions of the clutch base and the clutch cover, in a manner such that each pressing force adjusting means is capable of pivoting movement for changing an axial position of the pressing plate and adjusting a magnitude of pressing force which is applied to the multiple disc clutch member, depending upon a magnitude of centrifugal force generated by rotating force which is transferred from the flywheel.